MAX6978 Overview
Description
The MAX6978 serial-interfaced LED driver provides eight open-drain, constant-current sinking LED driver outputs rated at 5.5V. The MAX6978 operates from a 3V to 5.5V supply.
Key Features
- for safetyrelated applications, which blanks the display if the serial interface fails
- If the serial interface becomes inactive for more than 1s, all driver output latches are automatically cleared
- This turns off all LEDs connected to the outputs
- The shift register data is not disturbed
- The watchdog function requires no software change to the application driving the MAX6978
- The MAX6978 uses the industry-standard shift-registerplus-latch-type serial interface
- The driver accepts data shifted into an 8-bit shift register using data input DIN and clock input CLK
- Input data appears at the output DOUT eight clock cycles later to allow cascading of multiple MAX6978s
- The latch-enable input LE loads the 8 bits of shift-register data into an 8-bit output latch to set which LEDs are on and which are off
- The outputenable input OE gates all eight outputs on and off, and is fast enough to be used as a PWM input for LED intensity control
